Tarry mechanism for grinding machines



Oct. 25, 1932. H. E. BALSIGER 1,885,070

- I TARRYVMECHANISM FOR GRINDING MACHINES v 7 Filed April 15', 1927 ZSheets-Sheet 1 Oct. 25, 1932. H. E. BALSIIGER TARRY MECHANISM- FOR GRINDING MACHINES Filed April 15, 1927 v 2 Sheets-Sheet 2 INVENTQR. Harold lijalszgez:

A TORNEY Patented Oct. 25, 1932 UNITED STATES PATENT orrrcr.

HAROLD E. BALSIGER, OF WAYNESBORO, PENNSYLVANIA, ASSIGNOB. TO LANDIS TOOL COMPANY, OF WAYNESIBORO, PENNSYLVANIA, A COIBPORATION TARRY MECHANISM FQR GRINDING MACHINES- Application filed April 15,

My invention relatesto tarry mechanism vfor work carriages and is designed particularly for use on grinding machines or the like for the purpose of causing a dwell in the movement of the work carriage at the end of its travel before reversing the same. I

An object of the invention is to provide a tarrying device in which the period of dwell may be controlled within predetermined limits.

Another object of the device is to provide means whereby the movement of the carriage may be checked before reaching the limit of its travel in order to prevent its being stopped abruptly. 3 I

A further object is to provide a self-contained mechanism which is entirely separate from the driving mechanism.

Further objects and advantages will become apparent as the nature of the invention is more fully set forth in the appended description. Referring to the accompanying drawings which are made a part hereof and on which similar reference characters indicate similar parts,

Figure 1 is a sectional front elevation on the line 1-1 of Fig. 2 with'an additional sectional elevation of a reversing valve for a hydraulic motor showing two positions of said valve for corresponding positions of the reversing lever.

Figure 2 is a sectional plan view of the device through 22 of Fig. 1.

Fi re 3 is a sectional end the hue 33 in Fig. 1.

elevation along Figure 4 is a partial sectional end elevation on the line 44 in Fig. 2.

Figure 5 is a vertical section of the reversing valve.

Figure 6 is a diagrammatic front elevation of a grinding machine showing the location and method of operation of my device.

Figure 7 is a section on line 7-7 of Figure 6, the view being partially diagrammatic.

The device consists of a casting 10 containing two preferably cylindrical chambers 11 and 12. The chamber 11 is provided with openings 13 and 14 through which oil or other liquid is putinto and withdrawn from the reservoir 11 by means of passages 18 1927. Serial No. 184,161.

the chamber. These openings are closed by screw plugs 15 and 16. The chamber 12 consists of an enlargedlower portion 12 and a relatively smaller portion 17 The upper portion of the chamber 12' is connected with and I9. A needle valve 20 having a valve stem 21 controls a passage 22 between the passages 18 and 19. A piston 23 and a plunger rod 24 are positioned within the enlarged M cylinder 12' and the smaller portion respectively. The piston 23 is hollowed out to receive a valve seat 25 suitably mounted therein. The valve seat is provided p'referably with a plurality of ball-valves 26. A ,5 singlecheck valve would act satisfactorily under inost circumstances. A compression spring 27 seated against a cap 28 which closes t e cylinder and against a shoulder on the piston urges the piston in an upward direction. A plurality of ports 31 connect the interior of the piston with the chamber 12' 7 above the piston. A passage 32 connects the reservoir 11 with the lower part of the chamber 12' An extension 33 on the plungerrod 24 is provided with an invertedV-shaped head 34. Mounted upon the bed of the machine is a reversing lever 35. This lever is pivoted upon .a stud 36 von the machine and'is provided' with a spherical knob 37 at the upper end and a roller 38 at its'lower end. The roller 38 is adapted to engage the cam surfaces 39 on the block 34-. The reversing lever 35 isoperated by dogs 40 and 41 upon the traversing'carriage on the machine. As shown in Fig.5, dogs 40 and 41 are positioned upon the traverse carriage 42 and adaptedto engage the lever 35. As the carriage reaches approximately the end of its 1 travel in one direction, the dog moves the lever slightly past the vertex of the triangular cam 34. The spring 27 acting against the lower part of the piston tends to force the lever 35 the remainder of the way. The liquid trapped above the piston prevents rapid returnof the piston. Mounted on the base 43 of the machine is a reversing valve casing 44. This casing isprovided with an inlet port 45 connected with a suitable source of fluid under pressure. Triangular ports 46 and 47 connect the port 45 of the same fluid inotor.

' fluid motor, not shown, and be exhausted through theport 48 at the right hand side of the piston 51. This will operate the fluid motor to drive the carriage in one direction. When the pistons 51 and 52 are moved to the left hand side of the valve casing, the inlet port 45 willbe connected with the port'46 and the piston 51 will shut-01f access to the port 47 whereupon the fluid motor will be.

operated in a reverse direction to reverse the carriage. When the pistons 51 and 52 are in the position shown in dotted lines at 53 and 54, the port 45 is shut-01f from both the ports 46 and 47. When in this position, the motor is inoperative. The valve stem 50 is connected by means of the rod 50 with the reversing lever 35.

As shown in Fig. 1, when the reversing lever is in the position shown in full line at A, the valve stem 50 with the controlling pistons are at the extreme right hand end of the valve casing. Whenin this position, the work carriage will be at the extreme left hand end of its travel, as shown in Fig. 5, and the inlet port 45 is connected with the port 47 to deliver motive fluid to the fluid motor to drive the carriage 34 to the right as shown in Fig.

' 5. When the carriage has reached a point near the end of its travel toward the right, the dog 40 Wlll engage the lever 35 and carry it to position shown in dotted lines indicated at C, Fig. 1-. This will bring the pistons 51- and 52 to close the ports 47 and 46 respectively. The motor is then inoperative.

A roller 38, it will be observed, is resting upon the cam surface 39 upon the triangular wedge or cam 34 and the piston 23 has been forced down in the chamber 12'. The liquid trapped above the check valves 26 and 27 will prevent a quick return of the piston by the spring 16. The liquid above the piston,

however, will gradually be forced through the passa es 18 and 19 and the needle valve 20 into the c amber 11. As the liquid above the piston 23 escapes the piston will rise and the cam surface 39, acting on the roller38, will force the lever 35to the osition shown in dotted lines at D. This Wlll carry the valve stem 50 to the extreme left of the valve casing to uncover valve port 46 and connect the inlet 45 with the inlet 46 to the fluid motor to reverse the motor and. return the carriage again to the left. 4

It will be observed, that the valve ports 46 aesaovo and 47 are triangular in shape. lhis allows a gradual closing of the ports as the pistons are moved across them, with the result that the motive fluid is gradually cut-ofl' and the carriage instead of being abruptly stopped is first slowed down and then brought to a. position of rest. The interval between'the periods of travel of the work carriage may be predetermined by the needle valve 20 which determines the time in which the oil is forced through the passages 18 and 19 to allow the piston, with the piston rod and the cam attached thereto, to return to the uppermost position.

While my device. has been shown in connection with a fluid motor, it will be apparent that it is not limited in its use to such a motor.

Obviously, it might be adapted for use with a work carriage operated by an electric motor in which case a predetermined dwell between the movement of the carriage might be provided. The lever 35, in this case, might be attached through suitable mechanism to a rheostat for controlling the electric motor or the scribed in the specification, but only as set forth in the appended claims.

Having thus ully described my said invention, what I claim as new and desire to secure by Letters Patent, is: v

1. Inja machine tool having a reciprocating carriage, and a reversible hydraulic carriage drive mechanism, a reversing valve for said mechanism, a leverfor operating said valve, I

a plunger having a cam engageable with said lever for throwing said lever past central position, a spring urging said plunger t0- ward said lever and means actin in opposition to said spring for retarding t e action of said plunger whereby said lever will remain in central position for a predetermined length of time, substantially as set forth.

2. Reversing mechanism for the work carriage of a grinding machine comprising a motor for operating said carriage, a valve controlling admission of fluid to said, motor, a

lever engageable with means for operating said valve, means on the work carriage for engaging said lever at each end of travel of the carriage, for shifting, the lever to move the valve to the position to stop the motor, a dashpot controlled plunger having a cam engag ing the lever to reverse the valve to reverse the motor, said plun ger being movable in one direction by the said lever and in its return direction by a spring, and restricted fluid pressure means acting in opposition to the said spring, said restricting means causing the said valve to stop in inoperative position for a predetermined time to cause a dwell of the carriage at each end of its travel, substantially as set fdrth.

3. A tarry device for the work carriage of a grinding machine com rising a reverslng valve, a lever operated y the carnage for shifting said valve, a spring loaded plunger having a cam engageable with the saidlever to complete the reversal of the said lever and self contained pressure fluid m ans operating in opposition to the said spring to delay the action of said plunger, substantially as set forth.

4. In a grinding machine, a traverse carriage, a driving mechanism for traversing said carriage, a reversing mechanism for reversing said driving mechanism, a reversing lever to operate said reversing mechanism, means on the carriage adapted to initiate a reversal of said lever to move the reversing mechanism to a position to stop the carriage,

a spring pressed plunger operable to complete the reversing movement of the lever to reverse the driving mechanism, and self contained pressure fluid means operating in opposition to the said spring to delay the action of the said plunger, substantially as set forth. 5. In a machine tool having a reciprocating carriage, a tarry device comprising a reversible hydraulic carriage drive mechanism, a reverslng valve for said mechanism, shifting mechanism for operating said valve, a sprin operated cam and plunger for operating sai shifting mechanism to shift said valve past J central position, and self-contained means for retarding the action of said cam whereby said ,valve will remain in central position for a predeterminedlength of time, substantially as set forth. a

6. In a grinding machine, a traversecarriage, a driving mechanism for traversing said carriage, a reversing mechanism for reversing said driving mechanism, means to operate said reversing mechanism, devices on the carriage adapted to engage and shift said operating means to shift the reversing mechanism to position to stop the carriage, resilient means operable to complete the shifting movement of said operating means to reverse the driving mechanism, and self contained pressure fluid means operating in opposition to said resilient means todelay the action of said resilient means, substantially as set forth.

In witness whereof, I have hereunto set 111 hand at WVaynesboro, Pennsylvania, this 12t day of April, A. D. nineteen hundred and twenty-seven.

- HAROLD E. BALSIGER. 

